Java ByteBuffer Search unsignedBinarySearch(final ByteBuffer array, int position, final int begin, final int end, final short k)

Description

Look for value k in buffer in the range [begin,end).

License

Apache License

Parameter

Parameter	Description
array	buffer where we search
position	starting position of the container in the ByteBuffer
begin	first index (inclusive)
end	last index (exclusive)
k	value we search for

Return

count

Declaration

public static int unsignedBinarySearch(final ByteBuffer array, int position, final int begin, final int end,
        final short k) 

Method Source Code

//package com.java2s;
/*/*from   w ww  .  ja v a  2 s . c o m*/
 * (c) the authors Licensed under the Apache License, Version 2.0.
 */

import java.nio.ByteBuffer;

import java.nio.ShortBuffer;

public class Main {
    /**
     * Look for value k in buffer in the range [begin,end). If the value is found, return its index.
     * If not, return -(i+1) where i is the index where the value would be inserted. The buffer is
     * assumed to contain sorted values where shorts are interpreted as unsigned integers.
     *
     * @param array buffer where we search
     * @param begin first index (inclusive)
     * @param end last index (exclusive)
     * @param k value we search for
     * @return count
     */
    public static int unsignedBinarySearch(final ShortBuffer array, final int begin, final int end, final short k) {
        return branchyUnsignedBinarySearch(array, begin, end, k);
    }

    /**
     * Look for value k in buffer in the range [begin,end). If the value is found, return its index.
     * If not, return -(i+1) where i is the index where the value would be inserted. The buffer is
     * assumed to contain sorted values where shorts are interpreted as unsigned integers.
     *
     * @param array buffer where we search
     * @param position starting position of the container in the ByteBuffer
     * @param begin first index (inclusive)
     * @param end last index (exclusive)
     * @param k value we search for
     * @return count
     */
    public static int unsignedBinarySearch(final ByteBuffer array, int position, final int begin, final int end,
            final short k) {
        return branchyUnsignedBinarySearch(array, position, begin, end, k);
    }

    protected static int branchyUnsignedBinarySearch(final ShortBuffer array, final int begin, final int end,
            final short k) {
        final int ikey = toIntUnsigned(k);
        // next line accelerates the possibly common case where the value would be inserted at the end
        if ((end > 0) && (toIntUnsigned(array.get(end - 1)) < ikey)) {
            return -end - 1;
        }
        int low = begin;
        int high = end - 1;
        while (low <= high) {
            final int middleIndex = (low + high) >>> 1;
            final int middleValue = toIntUnsigned(array.get(middleIndex));

            if (middleValue < ikey) {
                low = middleIndex + 1;
            } else if (middleValue > ikey) {
                high = middleIndex - 1;
            } else {
                return middleIndex;
            }
        }
        return -(low + 1);
    }

    protected static int branchyUnsignedBinarySearch(final ByteBuffer array, int position, final int begin,
            final int end, final short k) {
        final int ikey = toIntUnsigned(k);
        // next line accelerates the possibly common case where the value would be inserted at the end
        if ((end > 0) && (toIntUnsigned(array.getShort(position + (end - 1) * 2)) < ikey)) {
            return -end - 1;
        }
        int low = begin;
        int high = end - 1;
        while (low <= high) {
            final int middleIndex = (low + high) >>> 1;
            final int middleValue = toIntUnsigned(array.getShort(position + 2 * middleIndex));

            if (middleValue < ikey) {
                low = middleIndex + 1;
            } else if (middleValue > ikey) {
                high = middleIndex - 1;
            } else {
                return middleIndex;
            }
        }
        return -(low + 1);
    }

    protected static int toIntUnsigned(short x) {
        return x & 0xFFFF;
    }
}

Related

1. indexOf(ByteBuffer buffer, ByteBuffer pattern)
2. indexOf(ByteBuffer buffer, ByteBuffer pattern)
3. indexOf(final ByteBuffer buf, final int c, final int start, final int end)
4. indexOf(final ByteBuffer haystack, byte[] needle)
5. search(ByteBuffer buffer, int n, byte[] param)